Sorry for the messy handwriting
There are many ways, but here is one:
x = 100
Since ‘x’ is 100 and we want 100 more, we just need to add ‘x’ to 623
Answer: x + 623 (Make sure you define your ‘x’ value)
To subtract vectors, you simply have to subtract correspondent coordinates.
So, if you have

the subtraction is simply

So, in your case, we have

Answer:
xy-49
Step-by-step explanation:
x x y is xy and -7x7 is 49 so the answer is xy- 49
The astronomer has to choose 3 star images out of 8.This is a problem of combinations. This can be expressed as 8C3 i.e. combination of 8 objects taken 3 at a time.
This means, if 8 images are nearby the astronomer will have 56 choices <span>
of the three stars.</span>